It is known in the art to provide apparatus for dermal abrasion and the cleansing of exposed in vivo tissue. There are a multiplicity of applications to both humans and animals during surgical procedures where the removal from the tissue surface of solid contaminants, such as fibers, dust, sand particles, and the like, as well as organic matter, such as puss, fats, and others, is necessary.
In addition, such cleansing is necessary in preparation prior to and/or subsequent to treatment for dental conditions such as gingivitis, caused by the long-term effects of plaque deposits. Unremoved plaque mineralizes into a hard deposit called calculus (tartar) that becomes trapped at the base of the tooth. It is also necessary to remove the toxins produced by the bacteria.
Organic matter including the outer dermal layer tends to bond to tissue much more strongly than non-organic matter, and is generally more difficult to remove. Accordingly, while non-organic matter is removable from the tissue by means of a liquid stream, it is often not possible to remove some organic matter in this way. More specifically, and most problematic, are those particles which are smaller than the thickness of the boundary layer of the fluid stream which is formed on the tissue surface during irrigation with a liquid such as water. The boundary layer is characterized by having a fluid velocity which reduces sharply adjacent to the flow surface, and which is virtually zero at the surface.
The smallest particles located in the boundary layer exhibit a drag resistance of a magnitude sufficient for these particles to remain attached to the surface and to resist being swept away by the fluid stream, even if this has an overall very high velocity.
A number of cleansing devices and systems have been developed to improve the cleansing of a variety of surfaces. To attempt solve this problem, there have been developed a number of prior art devices such as disclosed in U.S. Pat. Nos. 3,982,965, 4,350,158, 4,681,264, 4,982,730, 5,046,486, 5,551,909, 6,199,773, 6,203,406, 6,454,871 and GB1008503. These devices operate on the basis of providing a liquid stream with a reduced boundary layer thickness employing fluid and air nozzle assemblies, a high velocity aerosol of at least partially frozen particles, and pulsed jets of liquid sprayed on to a metal surface in order to sweep away small particles. These devices, however, generally have complicated constructions, use very large quantities of liquid, and have been found to provide only a small improvement over non-pulsed spray devices.
Referring now to U.S. Pat. No. 5,730,806 entitled “Gas-liquid supersonic cleaning and cleaning verification spray system” to Caimi, et al. on Mar. 24, 1998, there is disclosed a gas-liquid cleaning spray system which employs one or more converging-diverging nozzles to accelerate a gas-liquid mixture to a supersonic velocity for cleaning various types of articles, such as mechanical, electrical and fluid components.
Referring now to U.S. Pat. No. 6,293,498 and U.S. Pat. No. 6,360,992 entitled “Hybrid deicing system and method of operation” to Stanko, et al. on Sep. 25, 2001 and Mar. 26, 2002 respectively, there is disclosed an invention which overcomes the disadvantage of the prior systems and produces a high velocity specially formed and constituted pressure aerodynamic stream system for efficiently and effectively removing ice from an aircraft.
Referring now to U.S. Pat. No. 5,100,412 entitled “Apparatus for making micro-abrasions, particularly on human tissue or on hides” to Rosso on Mar. 31, 1992 there is disclosed apparatus for making micro-abrasions, particularly on human tissue, which includes a handle having an aperture which is intended to be positioned on the surface to be treated, and a nipple device for the metered supply of reducing substances in a pneumatic carrier to the aperture of the handle. The supply device comprises only a vacuum source connected to the handle to draw the reducing substances towards the aperture of the handle. A collector device is provided for collecting the used substances for disposal.
Referring now to U.S. Pat. No. 5,207,234 entitled “Method for making micro-abrasions on human tissue” to Rosso on May 4, 1993, there is disclosed a method for making micro-abrasions on human tissue. The method includes placing a handle having an open chamber therein on human tissue to close the chamber, applying suction to the chamber to sealingly engage the periphery of the chamber with the human tissue and partially sucking the human tissue into said chamber. This induces the flow of air into the chamber by the removal of air from the chamber by suction while restricting entry of ambient air from the surrounding atmosphere into the chamber around the periphery of the chamber, entraining a reducing substance in said flow of air prior to entry of the flow of air into the chamber. This directs the reducing substance entering the chamber against the human tissue at an angle less than 90 degrees, entraining used reducing substances and abraded tissue in the flow of air being removed from the chamber by suction and collecting used reducing substances and abraded tissue in a manner to prevent reuse of the reducing substances during continued application of a vacuum to the chamber.
Referring now to U.S. Pat. No. 5,810,842 entitled “Equipment for microdermoabrasion through a flow of an air/reducing substances mix” to Di Fiore, et al. on Sep. 22, 1998, there is disclosed a device for microdermoabrasion using a flow of a mixture of air and reducing substances. The device comprises a casing with a vacuum pump and a compressor at an interior of the casing. The device further comprises a control footswitch for actuating the compressor, a mixing bulb and a collecting bulb at an exterior of the casing, and a handpiece extending between the mixing bulb and the collecting bulb. The mixing bulb contains a mixture of air and reducing substances.
Further, there have been developed a multiplicity of dental cleaning devices, which operate to clean teeth, cavities and spaces between the teeth. Some such devices also address the problem of gingivitis. Included amongst such devices are U.S. Pat. Nos. 5,013,241, 5,203,698, 5,273,428, 5,387,182, 5,667,483, 6,120,755, 6,224,378, 6,497,572 and DE19654098, FR2654331, FR2599244, DE3726349.
Referring now to Israel Patent No. 118801 entitled “Apparatus and Method for Cleansing Tissue” to M. Tavger on Dec. 16, 2001, there is disclosed apparatus employing liquid and gas as working fluids for cleansing living tissue, which includes: a container for a sterile liquid; a fluid delivery head having a liquid entry port and a gas entry port, fluid outlet apparatus, and valve apparatus located between the entry ports and the fluid outlet apparatus and for selectably permitting respective liquid and gas flows from the entry ports to the fluid outlet apparatus; liquid conduit apparatus extending between a liquid inlet located within the container and a liquid outlet connected to the liquid entry port of the delivery head; gas conduit apparatus extending between a gas inlet and a gas outlet, wherein the gas inlet is connected to a source of pressurized gas and the gas outlet is connected to the gas entry port of the delivery head, and wherein the gas conduit apparatus is connected to the container via an intermediate outlet port; and apparatus for selectably exposing the source of sterile liquid to a flow of pressurized gas flowing from the gas inlet to the gas outlet and into the gas entry port of the fluid delivery head, thereby to pump the sterile liquid along the liquid conduit apparatus, from the inlet to the outlet, and into the liquid entry port of the fluid delivery head, wherein the fluid outlet apparatus comprises a gas-liquid combining member arranged to receive the gas and liquid flows and to combine them into a gas-liquid outflow which is operative to exit the apparatus through the fluid outlet in the form of a sterile liquid mist suspended in a high velocity gas stream.
Referring now to Israel Patent No. 122016 entitled “Apparatus for Dermal Abrasion” to M. Tavger on Dec. 16, 2001, there is disclosed a method of dermal abrasion, which includes exposing a source of sterile liquid to a flow of pressurized gas, thereby causing a pumped supply thereof into a fluid delivery head; supplying the pressurized gas to the fluid delivery head; and combining the gas and liquid supplied to the delivery head; this fluid delivery head having a fluid outlet with a predetermined internal diameter, so as to provide a gas-liquid outflow in the form of a sterile liquid mist jet suspended in a high velocity gas stream; and exposing to the mist jet, at a preselected distance from the fluid outlet, a portion of the skin surface sought to be abraded, thereby separating therefrom at least a portion of the epidermis and removing therefrom the resulting tissue debris.
Many of the dermal abrasion and cleansing devices disclosed hereinabove have a specific drawback, when employed for tissue abrasion or skin peeling. The relatively high flow rate of liquid employed by the above-mentioned cleansing devices reduces the cleansing and scouring effect as a result of the development of a virtually stagnant boundary layer over the surface to be cleaned. There is a need in the art, notably in relation to dermal abrasion and to cleansing tissue surfaces or cavities, to avoid boundary layer formation during the cleansing process by utilizing a minimal flow of liquid.